Sophie Turner and Maisie Williams don't just play sisters on television—they're practically sisters IRL. The fictional Stark siblings but real life besties have a deep bond that extends far beyond the seven kingdoms of Game of Thrones: We've seen the two get matching tattoos, have each other's back on the red carpet, and even get fake married. And now, Sophie Turner and Maisie Williams—A.K.A. Mophie—are doing something only true best friends can get away with: They are dishing each other's most embarrassing moments.

It all started when Sophie Turner first appeared on BBC's Radio 1, and the host, Nick Grimshaw, reached out to Williams to reveal cringeworthy secrets about Turner. At the time, Williams shared that Turner has a male invisible friend named Angelbert Wilson. "Who, friend to friend, is weird," Williams said to Grimshaw when she recently appeared on the show. "This was like, when she was at secondary school—like 14, 15 years old," Williams continued. "[She] created a Facebook page and everything...She even just invited him to her birthday party event that she's going to have for her 21st."

Now, Sophie Turner is returning the favor and sharing an equally mortifying story about Maisie Williams. Turner told Grimshaw to ask Williams about Bono, which led to Williams admitting one of her most embarrassing moments. "We were lucky enough to get U2 tickets when we were in Belfast shooting," Williams said. "Bono was there backstage, saying hi to everyone. And I didn't want to do the thing, like, 'I know who you are.'"

So instead? "I'd had a drink, and he goes, 'Hi, what's your name?" Williams recalled. "I said, 'I'm Maisie'—and I went to say 'what's your name,' which you can't say to Bono."

Naturally, Turner—who was there—wouldn't let Williams live it down. "Sophie was like, 'You just asked Bono what his name was at a U2 concert," Williams said. "It was awful."

But in true BFF fashion, Sophie Turner and Maisie Williams are still thisclose—despite embarrassing each other on national radio.